From: cgsoftlabs on
it is not bacteria...

nowadays root filling materials contains antibacterial substances which
can kill 99.99% of what's inside;
wait few more days for the periapical tissue to heal...if not..go to
your dentist and make a RX;
it's like when you "pin-prick" your finger...it takes a while to heal.

Best Regards
Christian Gheorghe

From: dr shad j lewis (via google) on
It should. Most likely this is the case. A small amount of root
canals have to be re-treated.

The important thing is the end of the root is plugged up good. Then
things should resolve.